Field of the Invention and Related Art Statement
This invention relates to an electronic endoscope apparatus provided with a means of simultaneously displaying an original picture image and special picture image for a video signal.
Recently a medical is extensively used whereby organs within a body cavity can be observed with an elongate insertable part inserted into the body cavity or, as required, various therapeutic treatments are made using treating instruments inserted through a treating instrument channel and an industrial is extensively used whereby the interiors of boilers and engines can be observed with an insertable part inserted into them.
There are also suggested various electronic endoscopes of a system wherein a solid state imaging device as a charge coupled device such (CCD) is provided as an imaging means in the tip part of an insertable part so that picture image information may be taken out as a photoelectrically converted electric signal.
FIG. 1 shows an example of an electronic endoscope apparatus considered to be a related art example.
In FIG. 1, an illuminating light emitted from a light source apparatus (not illustrated) is led to a tip part 83 by a light guide 82 of an electronic endoscope 81 and is radiated to an object 85 through a light distributing lens 84. An image of this object 85, formed by this illuminating light, is formed on a solid state imaging device 87 by an image forming optical system 86. The signal photoelectrically converted by this solid state imaging device 87 is transmitted to a video signal processing circuit 89 through a cable 88, is processed as fixed and is output as video signals as, for example, NTSC and R, G and B signals which are displayed as video images by a color monitor 91 or the like.
The output of the solid state imaging device 87 is input into the video signal processing circuit 89, various noise contained in the solid state imaging device output are reduced in a noise reducing circuit 92, .gamma. is corrected in a .gamma.-correcting circuit and a luminance signal Y and color difference signals R-Y and B-Y are generated by a luminance/color difference separating circuit 94. The luminance signal Y increases the sharpness by an outline correcting circuit 95 and is input together with the color difference signals R-Y and B-Y into an encoder circuit 96 and a video signal is output.
The above mentioned outline correcting circuit 95 is of a formation as is shown in FIG. 2. The output E of the outline correcting signal generating circuit 97 is made G times as large by a coefficient counter 98 as shown in this diagram and is added to a luminance signal Y' in an adder 99. In such a case, the outline correcting amount can be varied by varying the value of the coefficient G of the coefficient counter 98.
The outline correcting system by the above mentioned outline correcting signal generating circuit 97 is largely divided into a horizontal outline correction and vertical outline correction. A horizontal outline correcting signal generating circuit is shown in FIG. 3. A block diagram of a vertical outline correcting signal generating circuit is shown in FIG. 4.
FIGS. 3a and 4a are respectively of a primary outline correcting system wherein a signal equivalent to a primary differential is generated. FIGS. 3b and 4b are respectively of a secondary outline correcting system wherein a signal equivalent to a secondary differential is generated. In FIG. 3a, the luminance signal Y is delayed by about .tau.=200 [ns] by a delay line 101, is input into an adder 102 and is directly output as a luminance signal Y'. The output of the above mentioned delay line 101 is output as a signal E with the signal Y added in the above mentioned adder 102 through a coefficient counter 103 making -1 time.
In FIG. 3b, the luminance signal Y is delayed by .tau. in the delay line 104 and is input into an adder 105. The output of this delay line 104 is input into a delay line 106 delaying further by .tau. and is input into an adder 107 and is also output as a luminance signal Y'.
The output of the above mentioned delay line 106 is added in the adder 105 and the output of this adder 105 is input into the above mentioned adder 107 through a coefficient counter 108 making -1/2 time and is output as an outline correcting signal E with the luminance signal Y' added.
FIGS. 4a and b are of the same formation as the formation replaced with delay lines 101', 104' and 106' delaying by 1H (one horizontal scanning period) the delay amounts .tau. of the delay lines 101, 104 and 106 in FIGS. 3a and b.
The input signal Y and outputs E and Y' in (FIGS. 3a and b are used as the outline correcting signal generating circuit 97 of the above mentioned FIG. 2 are shown in FIGS. 5 and 6.
A block diagram of an outline correcting signal generating circuit combining these horizontal outline correcting system and vertical outline correcting system is shown in FIGS. 7a and b.
In the outline correcting signal generating circuit shown in FIG. 7a, the luminance signal Y is output directly as a signal Y' and is input into the .tau. and 1H delay lines 111 and 112 and the outputs of these delay lines 111 and 112 are added in the adder 113 and then the addition is input into a coefficient counter 114 making -1/2 time. The output of this adder 114 is added with the input signal Y in an adder 115 and an output signal E is output.
In FIG. 7b, the input luminance signal Y is input into .tau. and 1H delay lines 121 and 122. This signal delayed by 1H is input into a 1H delay line 123 and into a .tau. delay line 124 and adder 125. The output of this delay line 124 is further input into a .tau. delay line 126 and into an adder 127. The output of the above mentioned delay line 123 is also input into an adder 125 through a .tau. delay line 128 and the output of this adder 125 is input into a coefficient counter 129 making -1/4 time. The output of this coefficient counter 129 is output as an output signal E through the adder 127. The output of the delay line 124 is output as an output signal Y'.
One of the picture image processes of this video signal is a differentiating process. By making this process, the outline of a picture image can be extracted, the structure and the like of an object can be observed and, for example, for medical use, the structure of an affected part can be observed in detail from the observation of the boundary of the affected part. Particularly, in the above mentioned differentiating process, not only the outline can be extracted but also the manner of the inclination of the rise and fall of the object can be observed.
This process has been heretofore made by an external picture image processing apparatus as a computer by using the output of a video signal processing circuit. As a simple process, there is a suggestion of outputting an outline correcting signal as it is.
However, even if an outline corrected signal or a differential processed picture image is output, it will not be able to be compared with the original picture image and therefore the feature will not be well developed. For example, even if the structure of a part to be noted can be clearly output by enhancing the outline of an original picture image, it will not be able to be simultaneously compared and therefore its advantage will not be able to be well extracted.
For a differentiating process, the picture image will often be very different from the original picture image.
By this differentiating process, some part may be made conspicuous but an unclear part will often be produced.
Thus, with only one picture image, a general diagnosis will be difficult and will be hard to accurately make.
In U.S. Pat. No. 4,712,133, there is disclosed an endoscope apparatus wherein, irrespective of a still picture display, a moving picture is always displayed. However, with the still picture, the information is not very different from that obtained from the moving picture. Therefore, for general diagnosis, information different from that of the moving picture (original picture) is desired to be obtained.